Effect of water and DMSO on mechanoelectrical conversion of Schottky DC generators

This study demonstrates the important effect of water in polypyrrole (PPy) on the mechanical-to-electrical conversion of PPy-based Schottky DC generators. Increasing the water content in PPy significantly enhances device current outputs and slightly increases voltage outputs. When the water content in PPy was 10.49 wt%, the device's current output reached 262.60 μA, 31 times higher than that in the normal state (water content 6.67 wt% and current output 8.45 μA). However, current and voltage outputs decayed massively when the water content was reduced from 6.67 wt% to a lower level. The improved device performance caused by the high water content originated from the improved PPy conductivity and a larger reduction in the Schottky barrier height during device compression. We further showed that incorporating dimethyl sulfoxide (DMSO) into PPy stabilized the water content in PPy and enhanced the electrical outputs, especially when the water content was relatively low. 0.15 wt% DMSO in PPy containing 8.46 wt% water resulted in a device output of 105.90 μA cm⁻², 4.9 times higher than that of the DMSO-free PPy device. These novel findings may benefit the development of durable, high-performance Schottky DC generators.